US5167272A - Adjusting a mold additive for continuous casting - Google Patents

Adjusting a mold additive for continuous casting Download PDF

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Publication number
US5167272A
US5167272A US07/670,396 US67039691A US5167272A US 5167272 A US5167272 A US 5167272A US 67039691 A US67039691 A US 67039691A US 5167272 A US5167272 A US 5167272A
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United States
Prior art keywords
sio
cao
slag
additive
mgo
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Expired - Fee Related
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US07/670,396
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English (en)
Inventor
Shozo Shima
Yukio Nakamura
Masahiro Nakamura
Masanobu Kanayama
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Kamogawa Industry Co Ltd
Nippon Steel Corp
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Kamogawa Industry Co Ltd
Nippon Steel Corp
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Publication date
Application filed by Kamogawa Industry Co Ltd, Nippon Steel Corp filed Critical Kamogawa Industry Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • B22D11/111—Treating the molten metal by using protecting powders

Definitions

  • the present invention relates to a mold additive for continuous casting of steel.
  • Mold additives are used in continuous casting of steel for preventing oxidation of the surface of molten steel which contacts with the inner surface of the mold, heat retention, absorption of nonmetal inclusions and lubrication between the mold and the cast product.
  • a mold additive normally comprises metal oxides such as SiO 2 , CaO, Al 2 O 3 , MgO and MnO as a flux base material and, if necessary, a melting property regulator comprising metal oxides such as Na 2 O, K 2 O, Li 2 O, and B 2 O 3 and a metal fluoride such as CaF 2 , AlF 3 , NaF and LiF for regulation of melting point and viscosity and a carbonaceous powder for regulation of melting rate.
  • metal oxides such as SiO 2 , CaO, Al 2 O 3 , MgO and MnO
  • a melting property regulator comprising metal oxides such as Na 2 O, K 2 O, Li 2 O, and B 2 O 3 and a metal fluoride such as CaF 2 , AlF 3 , NaF and LiF for regulation of melting point and viscosity and a carbonaceous powder for regulation of melting rate.
  • the portion which contacts with the surface of the molten steel melts to form a molten slag layer and unmolten slag layer on the molten slag layer which cover the surface of the molten steel.
  • the molten slag layer generally used is mainly composed of 25-45 wt % of SiO 2 , 25-45 wt % of CaO, 1-20 wt % of Al 2 O 3 , 5-20 wt % of Na 2 O and 5-20 wt % of F, CaO/SiO 2 being 0.5-1.8 and has physical properties of a viscosity of 0.5-15 poises at 1300° C. and a melting point of 900° C.-1250° C.
  • Japanese Patent Kokai No. 60-234751 discloses a mold additive containing 3-35 wt % of a melting type oxide of 0.01-1 mm in particle size
  • Japanese Patent Kokai No. 57-41862 discloses a mold additive which is an additive for stationary casting comprising a flux base and, if necessary, a melting property regulator and additionally containing 0.5-15 wt % of zirconia.
  • the amorphous slag formed upon melting contains some bubbles. These bubbles result in nonuniform cooling of the cast product at the surface of the mold in continuous casting of steel, which causes not only defects in the surface of the cast product, but also break-out.
  • one or more of magnesia, alumina, forsterite, zircon, wollastonite and silica which have been once molten in an electric furnace to enhance fire resistance and reduce reactivity is used as a slag forming base material to increase the melting temperature of the flux after use.
  • Japanese Patent Kokai No. 57-41862 aims at preventing damage to the dipped nozzle by containing zirconia in the additive and this is not sufficient for decreasing bubbles in the molten slag.
  • the present invention which has been accomplished for effectively solving the above-mentioned problems is a mold additive for continuous casting which comprises an additive for stationary casting containing a flux base and, if necessary, a melting property regulator, characterized in that it contains 4-30 wt % of MgO and 4-30 wt % of ZrO 2 and that CaO/SiO 2 is within the range of 0.5-1.5.
  • FIG. 1 is a diagram which shows the state of formation of bubbles in molten slag when ZrO 2 and MgO are added with changing addition amount thereof to a conventional additive.
  • FIG. 2 is a graph which shows heat transfer coefficient depending on casting rate in the present invention and comparative example.
  • FIG. 3 is a graph which shows heat retaining property exhibited by the additive of the present invention and that of comparative example.
  • FIG. 1 shows the state of formation of bubbles in molten slag when a conventional additive to which ZrO 2 and MgO were added with changing amount thereof was used.
  • the additive of the present invention comprises a commercially available additive for stationary casting which contains a flux base to which MgO and ZrO 2 are added respectively so as to contain them in specific amounts and SiO 2 or CaO may be added so as to adjust the CaO/SiO 2 ratio to the specific one.
  • the additive of the present invention may comprise a commercially available additive for stationary casting which contains a flux base and a melting property regulator in a suitable ratio to which MgO and ZrO 2 are added respectively so as to contain them in specific amounts and SiO 2 or CaO may be added so as to adjust the CaO/SiO 2 ratio to the specific one.
  • MgO, ZrO 2 , CaO and SiO 2 may be used in the form of industrial chemicals as such or raw ores rich in them which are ground and sieved.
  • the inventors have succeeded in producing slag containing no bubbles by the simultaneous addition of high melting point materials, MgO and ZrO 2 to conventional additives to form a solid solution while keeping CaO/SiO 2 within a specified range.
  • additive A of the present invention having the composition as shown in Table 1.
  • Additive B of the present invention was prepared by adding CaO in the form of an industrial chemical to the additive A in such an amount that CaO/SiO 2 was 0.9.
  • four kinds of commercially available additives were used as conventional additives A, B, C and D.
  • a slag in the form of a solid solution which contains no bubbles exerts lubricating action between solidified shell and cooling mold in the continuous casting of steel and a good cast product can be obtained by a stable amount of heat removed.
  • the slag which flows between cooling mold and solidified shell does not form bubbles in the continuous casting, a cast product is uniformly cooled and as a result, as shown in FIG. 2, removal of heat in a stable amount can be attained on the surface of the cast product and besides, the heat-retaining property of the slag is excellent as shown in FIG. 3. For this reason, removal of heat in the cooled mold at casting is relaxed and the cast product is gently cooled whereby formation of deckle in the cooling mold can be prevented and occurrence of defects on the surface and inside of the cast product can be prevented.
  • the additive of the present invention is high in surface tension (Table 2) and in viscosity (Table 3) and nevertheless, it has a long break point time (Table 3) and the slag which flows between the cooling mold and solidification shell in the vicinity of meniscus part does not become a sticking layer and further, since it has a great specific gravity (Table 4), the proper amount of slag can be secured corresponding to a change in meniscus part and interface between the slag and molten steel. That is, it becomes possible to produce steels of from low carbon content to high carbon content by one formulation of additive.
  • bubbles are not generated in the molten slag in the mold and hence the conspicuous effects are exhibited that removal of heat in the cooling mold at casting is made uniform and defects on the surface and inside of the cast product can be prevented and besides there is no need to change additives depending on the kind of steel and thus a stable operation can be performed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
US07/670,396 1988-01-21 1991-03-15 Adjusting a mold additive for continuous casting Expired - Fee Related US5167272A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63009596A JPH01186253A (ja) 1988-01-21 1988-01-21 連続鋳造用鋳型添加剤
JP63-9596 1988-01-21

Related Parent Applications (1)

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US07465572 Continuation 1990-01-18

Publications (1)

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US5167272A true US5167272A (en) 1992-12-01

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US07/670,396 Expired - Fee Related US5167272A (en) 1988-01-21 1991-03-15 Adjusting a mold additive for continuous casting

Country Status (5)

Country Link
US (1) US5167272A (fr)
EP (1) EP0325274B1 (fr)
JP (1) JPH01186253A (fr)
KR (1) KR890011653A (fr)
DE (1) DE68901341D1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150211816A1 (en) * 2012-09-04 2015-07-30 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Aluminum composite material, heat exchanger, and flux

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03193248A (ja) * 1989-12-25 1991-08-23 Sumitomo Metal Ind Ltd 鋼の連続鋳造用モールドパウダー

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899324A (en) * 1973-03-16 1975-08-12 Scm Corp Flux for continuous casting of steel
FR2438685A1 (fr) * 1978-10-12 1980-05-09 Nippon Steel Corp Procede pour la fabrication de brames par coulee continue en vue de l'elaboration de toles a grains orientes
US4204864A (en) * 1978-04-19 1980-05-27 Scm Corporation Particulate slagging composition for the continuous casting of steel
US4235632A (en) * 1979-04-04 1980-11-25 Mobay Chemical Corporation Particulate slagging composition for the extended optimum continuous casting of steel
US4248631A (en) * 1979-05-02 1981-02-03 Wacker-Chemie Gmbh Casting powder for the continuous casting of steel and method for producing the same
JPS5741862A (en) * 1980-08-27 1982-03-09 Nippon Steel Corp Mold additive for continuous casting

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60234751A (ja) * 1984-05-07 1985-11-21 Nippon Steel Corp 鋼の連続鋳造用フラツクス

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899324A (en) * 1973-03-16 1975-08-12 Scm Corp Flux for continuous casting of steel
US4204864A (en) * 1978-04-19 1980-05-27 Scm Corporation Particulate slagging composition for the continuous casting of steel
FR2438685A1 (fr) * 1978-10-12 1980-05-09 Nippon Steel Corp Procede pour la fabrication de brames par coulee continue en vue de l'elaboration de toles a grains orientes
US4235632A (en) * 1979-04-04 1980-11-25 Mobay Chemical Corporation Particulate slagging composition for the extended optimum continuous casting of steel
US4248631A (en) * 1979-05-02 1981-02-03 Wacker-Chemie Gmbh Casting powder for the continuous casting of steel and method for producing the same
JPS5741862A (en) * 1980-08-27 1982-03-09 Nippon Steel Corp Mold additive for continuous casting

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
Japanese Abstracts 57 41862(A). *
Japanese Abstracts JP 60 234751(A). *
Japanese Abstracts-57-41862(A).
Japanese Abstracts-JP 60-234751(A).

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150211816A1 (en) * 2012-09-04 2015-07-30 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Aluminum composite material, heat exchanger, and flux

Also Published As

Publication number Publication date
EP0325274A2 (fr) 1989-07-26
JPH01186253A (ja) 1989-07-25
KR890011653A (ko) 1989-08-21
EP0325274A3 (en) 1989-10-25
EP0325274B1 (fr) 1992-04-29
JPH0372377B2 (fr) 1991-11-18
DE68901341D1 (de) 1992-06-04

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